//
// request_parser.hpp
// ~~~~~~~~~~~~~~~~~~
//
// Copyright (c) 2003-2013 Christopher M. Kohlhoff (chris at kohlhoff dot com)
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//

#ifndef HTTP_SERVER4_REQUEST_PARSER_HPP
#define HTTP_SERVER4_REQUEST_PARSER_HPP

#include <string>
#include <boost/logic/tribool.hpp>
#include <boost/tuple/tuple.hpp>
#include <boost/asio/coroutine.hpp>

namespace http {
  namespace server {

    struct request;

    /// Parser for incoming requests.
    class request_parser : boost::asio::coroutine
    {
    public:
      /// Parse some data. The tribool return value is true when a complete request
      /// has been parsed, false if the data is invalid, indeterminate when more
      /// data is required. The InputIterator return value indicates how much of the
      /// input has been consumed.
      template <typename InputIterator>
      boost::tuple<boost::tribool, InputIterator> parse(request& req,
          InputIterator begin, InputIterator end)
      {
        while (begin != end)
        {
          boost::tribool result = consume(req, *begin++);
          if (result || !result)
            return boost::make_tuple(result, begin);
        }
        boost::tribool result = boost::indeterminate;
        return boost::make_tuple(result, begin);
      }

    private:
      /// The name of the content length header.
      static std::string content_length_name_;

      /// Content length as decoded from headers. Defaults to 0.
      std::size_t content_length_;

      /// Handle the next character of input.
      boost::tribool consume(request& req, char input);

      /// Check if a byte is an HTTP character.
      static bool is_char(int c);

      /// Check if a byte is an HTTP control character.
      static bool is_ctl(int c);

      /// Check if a byte is defined as an HTTP tspecial character.
      static bool is_tspecial(int c);

      /// Check if a byte is a digit.
      static bool is_digit(int c);

      /// Check if two characters are equal, without regard to case.
      static bool tolower_compare(char a, char b);

      /// Check whether the two request header names match.
      bool headers_equal(const std::string& a, const std::string& b);
    };

  } // namespace server
} // namespace http

#endif // HTTP_SERVER4_REQUEST_PARSER_HPP
